This one is easy, and most of the commenters got it right. Here is how it went down in my simulation:
The bear is used to pulling things out of the water and eating them. Sharks usually either bump or "sample" their prey on the first pass. The shark approaches the bear, and attempts to bump him. The bear, rightly sensing the threat, attacks, raking the gills of the shark. Even though the shark is well over twice as big, never underestimate the power of a polar bear; their paws are like anvils with knives on them. The shark circles and comes back in for the kill. The shallow water limits his ability to generate the speed or leaping ability that makes sharks so dangerous, but he gets his razor sharp teeth into the bear's leg. The bear begins bleeding profusely, but not as fast as the shark. With a limited ability to remove oxygen from water, the shark is soon unable to move. Sharks that don't move die. Game over. The bear retreats to the ledge, and most likely bleeds out as well. But he can move on to the bear afterlife knowing he won this episode of "When Animals Fight."
On another note, my kid goes to private school, and they have a "Dad's Group." Last night I went for the first time, to a crab feed. Crabs remind me of water bugs, and I hate getting my hands dirty. There was a lot of ManCave talk, which makes me want to stick needles in my ears. Apparently my lack of desire for a large television makes me effete.
Actually, it was pretty fun, and Mr. French didn't just break his two beer limit rule; he blew through it, wadded it up, started it on fire, then peed on it to extinguish it. Then he came home and tried to sleep. I feel like ass, my eyes are nearly swollen shut, and my lovely bride told me I smelled horrible. I take great pride in being odor neutral, so this hurt. I am pretty sure someone slipped me a Mickey and filled my stomach with rotten meat. I so deserve this it isn't even funny. But I blame you, Jose. You could have stopped me and instead you let me use my own poor judgement.
Have a great weekend,